Reagent mixing apparatus

ABSTRACT

A mixing device adapted to bubble air through a sample solution in a reaction tube without disturbing the tube and without carrying any contaminating portion of the sample solution into the next tube whose sample solution is to be mixed by the same device. The device includes a cylinder having a piston connected with an air injecting probe adapted to be lowered into the reaction tube and to inject bubbles and thereafter to be retracted into the cylinder while at the same time wiping the exterior of the probe by means of a cylindrical curtain of air. Means are provided to retain the probe in retracted position until the next mixing cycle.

United States Patent 1191 Jones [111 3,740,041 1 51 June 19, 1973 [5 1REAGENT MIXING APPARATUS 2,975,119 3/1961 Emmons 92 15 ux 3,313,21541967 B 92 86 [75] Inventor Rlchm'dsm 3,535,206 /1970 Gft l nel...176/36 73 Assigneez Conner Chemistry, Inc, Maunabo 3,536,449 10/1970Astle 141/130 X Primary Examiner-Dennis E. Talbert Jr. 22 F1 d: t. 141971 i l l l 6 0c Attorney-Irving Sllvermann, Myron C. Cass, PP 139,311Sidney N. Fox et a1.

[52] U.S. Cl 261/64, /300 R, 23/253 R, [57] ABSTRACT/256,73/53,9l/52,9l/450,91/466, 92/15, 41 181 222/3 222 14 222 259 R, Amixing device adapted to bubble all through a sam- 261/3], 261/]2] plesolution in a reaction tube without disturbing the s 1 1 1m. (:1 Bold47/02 tube and Without Carrying any contaminating Portion of 58 Field ofSearch 261/64, 81, 121; the Sample Solution the "eXtmbe Whose sample 5555 25 3 5 15/300 73/53, 423 lution is to be mixed by the same device.The device in- R, 425 2 425 25 92/15 91/52, cludes a cylinder having apiston connected with an air 450, 449, 466, 462; 141/181, 129, 222/3,injecting probe adapted to be lowered into the reaction 143 5; 5 R tubeand to inject bubbles and thereafter to be retractedinto the cylinderwhile at the same time wiping 5 References Cited the exterior of theprobe by means of a cylindrical cur- UNITED STATES PATENTS tain of air.Means are provided to retain the probe in retracted position until thenext mixing cycle. 2,893,354 7/1959 Austin et al. 91/450 X 9 Claims, 2Drawing Figures PRESS. 1

s i Q 34 24 l 18 VENT s 1 1 1 54 S l l 52 4O PROGRAM 36 REAGENT MIXINGAPPARATUS BACKGROUND OF THE INVENTION In the art of automatic chemicalanalyzing apparatus, a plurality of reaction tubes passing through theapparatus is required to have the sample solutions mixed at some timeduring the passage. Mixing is best accomplished by injecting a stream ofbubbles in the sample solutions.

The problems involved include not disturbing the position of the tubesby raising or rocking or agitating the same so that the transportapparatus can be of simple construction, avoiding a complex airinjection apparatus for efficacy and economy and preventing theintercontamination between the sample solutions in the respectivereaction tubes.

The invention accomplishes the solution of these problems in a novel andsimplified manner. Other advantages of the invention will be obviousfrom the specification which follows.

SUMMARY OF THE INVENTION The apparatus of the invention has acylindrical member with a reciprocable piston on its interior. The upperend of the cylinder has a port above the piston and the lower end of thecylinder is also ported below the piston. A hollow probe is connected tothe bottom of the piston and a central constricted passageway permitsthe probe to be extended from and retracted into the cylinder. Theconstricted passageway is of a diameter slightly larger than the outerdiameter of the probe so that air may escape around the probe in acurtain under certain circumstances. The interior of the cylinder has agallery connected with the lower port below the piston and through whichthe probe extends and in addition connected with the constrictedpassageway.

Air applied under pressure to the top port will drive the pistondownwardly to cause the probe to extend into a reaction tube and at thesame time eject bubbles of air. Thereafter, air admitted to the bottomport will pass into the gallery, raise the piston and retract the probewhile at the same time forcing a curtain of air out the restrictedpassageway and thereby wiping the probe while it is being retracted.

Magnetic means hold the piston in its upper position with the proberetracted.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a median sectional viewthrough apparatus constructed in accordance with the invention showingthe environment in which it will be used and showing diagrammaticallyapparatus for operating the same; and

FIG. 2 is a chart used to explain the operation of the apparatus of FIG.1.

DESCRIPTION OF THE PREFERRED EMBODIMENT The reference characterdesignates the apparatus of the invention, the same being mounted in thedisposition shown to some suitable support (not shown) spaced above aline of reaction tubes 12 moving along a conveyor 14. Each tube has asample solution 16 therein which is to be mixed without disturbing thetubes 12 or interfering with their movement. Each tube is adapted to bestopped in its travel for a short time under the apparatus 10 and haveits sample solution mixed thereat.

The apparatus 10 comprises a cylinder 18 having a closure 20 at itsupper end providing a port 21 connected by the conduit 22 at the point Ato a pneumatic line leading to a suitable valve 24. The valve 24 enablesthe conduit 22 to be connected to a source of pressure 26 or to beclosed off. The lower end of the cylinder 18 has a lateral port 30connected by the conduit 32 at the point B to a pneumatic line leadingto the valve 24 and capable of being vented as at 34 or connected to thesource of pressure 26. The cylinder has a free piston 36 reciprocabletherewithin, and a central hollow probe 38 connects with the piston 36in such a manner that its upper end 40 opens above the piston. The lowerend or tip 44 of the hollow probe 38 may extend out of the cylinder 18by way of the conical plug 42 as shown in the drawing, or may beretracted! when the piston 36 moves upward, at which latter time the tip44 will be located at the point 46 shown in broken lines.

The port 30 opens into a gallery 48 formed in the plug 42 and connectingwith an axial passageway 50 slightly larger in diameter than the outerdiameter of the probe 38.

Preferably, the upper end of the piston 36 carries a magnetic disc 52adapted to cooperate with the lower surface of the closure 20magnetically so that at the upper end of the piston stroke, the piston36 will tend to remain adhered to the plug 20 .as shown by the brokenline outline at 36. The material of plug 20 and disc 52 may be anysuitable substance which can be permanently magnetized such as rubberwith iron powder mixed therein.

In operation, as shown in the chart of FIG. 2, assume that the piston 36is at the top of its stroke and the probe is fully retracted. A reactiontube 12 moves into the position shown directly below the device 10.Through a suitable programming device 54, the valve 24 is caused toprovide the connections designated step 1. Air pressure is applied tothe port 21 and the port 30 is vented to the atmosphere. Air enteringthe upper end of the cylinder 18 forces the piston 36 to leave itsmagnetic adherence to plug 20 and drives the piston 36 downwardlyextending the probe 33 into the sample solution 16 of the tube 12.Continued application of pressure causes bubblesshown at 56 to pass outthe end 44 which may be suitably restricted by a choke 58 to achieve thedesired size of bubbles. After a short period of time, at which the step2 occurs, with the connection to port 30 being either closed or vented,step 3 occurs.

In step 3, the valve 24 is operated to close conduit 22 so that the port21 is closed and the conduit 32 is connected to pressure source 26 sothat pressure is applied to the port30. Air entering the gallery 48exerts pressure against the bottom of the piston 36 raising it andstarting to retract the probe 38 from the sample solution 16. Since theport 21 is closed, air captured within the cylinder will escape to theopening 40 and pass down the interior of the probe 38 to clear itsinterior and bubble out of the solution while the probe is moving. Also,air passes down from the gallery 48 through the passageway 50surrounding the exterior of the probe 38 with a curtain of air at highpressure and blowing the moisture off the surface of the probe so thatwhen it is fully retracted it is dry. At this time, the piston 36 is inposition 36 poised for the next cycle. This is step 4 with both partsvented.

The ability to retract the probe 38 enables the bottom end of the plug42 to be positioned closely to the upper ends of the passing reactiontubes 12. Space is conserved thereby. The probe 38 is preferably made ofsoft plastic so that it is light in weight and so that any failure ofsynchronization of its operation with the movement of the conveyor 14will not result in jamming or breakage.

The valve 24 may comprise a plurality of valves to accomplish thedesired connections.

Modifications in the structure and programming and the valving sequenceand arrangement can be made without departing from the spirit or scopeof the invention as defined in the appended claims.

What it is desired to secure by Letters Patent of the United States is:

I claim:

1. A reagent mixing apparatus comprising:

A. a cylinder adapted to be poised over a moving line of reaction tubeswith the upper ends of the tubes passing close to the bottom end of thecylinder, said cylinder having an upper port and a lower port,

B. a piston reciprocable in the cylinder between the ports and having ahollow probe secured to the bottom end thereof with the probe having itsupper end opening to the top of the piston,

C. means closing off the top of said cylinder but for said upper port,

D. means closing off the bottom end of the cylinder but having a centralaxially extending passageway through which the probe may be extendedfrom and retracted into the cylinder,

E. a chamber formed within the cylinder below the piston at the bottomend of its stroke, connected with the lower port and being constructedand arranged to divide any air introduced through said lower port toraise the piston and retract the probe while at the same time blowingair through the central passageway around the periphery of the probewhile it is being retracted,

F. the upper port adapted to be connected to a source of air pressure sothat when such air pressure is applied thereto the piston will be drivendownwardly and extend the probe out of the bottom end of the cylinderwhile at the same time air will be passed through the probe and out thebottom end thereof, and

G. means for retaining the piston at the upper end of its stroke when noair is being introduced to the upper port.

2. Apparatus as claimed in claim 1 in which the closing off meanscomprise a plug in the bottom end of the cylinder and the chamber andaxially extending passageway are formed in the plug.

3. Apparatus as claimed in claim 2 in which the chamber comprises agallery coaxial with the passageway and having a diameter greater thansaid passageway, the lower end of the chamber being connected with saidpassageway so that the probe extends through the center of the gallerywhile the upper end of the gallery opens to the bottom of the piston.

4. Apparatus as claimed in claim 3 in which the lower port opens in alateral wall of said gallery.

5. Apparatus as claimed in claim 1 in which said retaining meanscomprise magnetically adherable structures on at least the facingsurfaces of the means closing off the top of the cylinder and the upperpart of the piston.

6. Apparatus as claimed in claim 1 in which the probe is formed oftubing of soft plastic material.

7. Apparatus as claimed in claim 1 in which the probe has asubstantially larger internal diameter throughout its major extent thanit has at its lower end.

8. Apparatus as claimed in claim 2 in which the means closing off thetop of the cylinder comprises a closure and the upper port comprises aconduit extending through the closure coaxially therewith.

9. The combination of the apparatus of claim 1 with a source of airpressure, venting means and valve means including connections to saidports and control means for connecting said upper port to said source ofpressure when said lower port is vented, for thereafter connecting thelower port to said source of pressure when said upper port is closed andthereafter venting both said ports.

1. A reagent mixing apparatus comprising: A. a cylinder adapted to bepoised over a moving line of reaction tubes with the upper ends of thetubes passing close to the bottom end of the cylinder, said cylinderhaving an upper port and a lower port, B. a piston reciprocable in thecylinder between the ports and having a hollow probe secured to thebottom end thereof with the probe having its upper end opening to thetop of the piston, C. means closing off the top of said cylinder but forsaid upper port, D. means closing off the bottom end of the cylinder buthaving a central axially extending passageway through which the probemay be extended from and retracted into the cylinder, E. a chamberformed within the cylinder below the piston at the bottom end of itsstroke, connected with the lower port and being constructed and arrangedto divide any air introduced through said lower port to raise the pistonand retract the probe while at the same time blowing air through thecentral passageway around the periphery of the probe while it is beingretracted, F. the upper port adapted to be connected to a source of airpressure so that when such air pressure is applied thereto the pistonwill be driven downwardly and extend the probe out of the bottom end ofthe cylinder while at the same time air will be passed through the probeand out the bottom end thereof, and G. means for retaining the piston atthe upper end of its stroke when no air is being introduced to the upperport.
 2. Apparatus as claimed in claim 1 in which the closing off meanscomprise a plug in the bottom end of the cylinder and the chamber andaxially extending passageway are formed in the plug.
 3. Apparatus asclaimed in claim 2 in which the chamber comprises a gallery coaxial withthe passageway and having a diameter greater than said passageway, thelower end of the chamber being connected with said passageway so thatthe probe extends through the center of the gallery while the upper endof the gallery opens to the bottom of the piston.
 4. Apparatus asclaimed in claim 3 in which the lower port opens in a lateral wall ofsaid gallery.
 5. Apparatus as claimed in claim 1 in which said retainingmeans comprise magnetically adherable structures on at least the facingsurfaces of the means closing off the top of the cylinder and the upperpart of the piston.
 6. Apparatus as claimed in claim 1 in which theprobe is formed of tubing of soft plastic material.
 7. Apparatus asclaimed in claim 1 in which the probe has a substantially largerinternal diameter throughout its major extent than it has at its lowerend.
 8. Apparatus as claimed in claim 2 in which the means closing offthe top of the cylinder comprises a closure and the upper port comprisesa conduit extending through the closure coaxially therewith.
 9. Thecombination of the apparatus of claim 1 with a source of air pressure,venting means and valve means including connections to said ports andcontrol means for connecting said upper port to said source of pressurewhen said lower port is vented, for thereafter connecting the lower portto said source of pressure when said upper port is closed and thereafterventing both said ports. >